1. Field of the Invention
The present invention relates to the game of golf. The invention concerns, more particularly, a weight positioning system for modifying a position of a center of gravity of a golf club head.
2. Description of Background Art
The formal origins of the game of golf, one of the oldest international sports, dates to the 16th century at The Royal and Ancient Golf Club at St. Andrews, located in Scotland. During successive centuries, the game of golf has gained and maintained a populous following due to inherent challenges of the game, a prestigious reputation, and its suitability for relaxation.
Growth in the number of individuals playing the game of golf provides an incentive for manufacturers of golf equipment, which includes golf clubs, balls, footwear, and bags, to improve upon the various features and characteristics of the golf equipment. Golf equipment has, therefore, evolved over time to provide enhanced performance and suitability for a wide range of playing abilities and styles. Many traditional golf balls, for example, included a wound, twine core and a balata rubber cover. More modern golf balls, however, may incorporate a solid core formed of polybutadiene, titanium, nickel, or cobalt, and a cover formed of ionomeric resin, surlyn, or polyurethane. Similarly, footwear intended for the game of golf traditionally utilized sharp, metallic spikes that provided a high degree of traction at the expense of damaging floors and other walking surfaces. In response, modern footwear incorporates polymer structures that provide a comparable degree of traction without damaging walking surfaces. Advances in golf club technology are also of particular interest to sporting goods manufacturers. Golf club shafts, for example, were often fashioned from wood, and are commonly formed of metal or graphite materials today. Whereas golf club heads of drivers were also fashioned from wood, modern drivers generally utilize heads formed of metals, such as steel, aluminum, or titanium.
A golf club head generally includes a substantially planar contact area for engaging a golf ball and propelling the golf ball in an intended direction. One factor that determines whether the golf ball is propelled in the intended direction relates to a position of a center of gravity of the golf club head. When the center of gravity is positioned behind the point of engagement on the contact surface, the golf ball follows a generally straight route. When the center of gravity is spaced to a side of the point of engagement, however, the golf ball may follow a route that curves left or right, which is often referred to as a hook or a slice. Similarly, when the center of gravity is spaced above or below the point of engagement, the route of the golf ball may exhibit a boring or climbing trajectory.
Most conventional golf club heads have a fixed center of gravity intended to accommodate a majority of the individuals that play the game of golf. Although golf club heads with a fixed center of gravity are popular among individuals that play the game of golf, systems permitting an individual to adjust or reposition the center of gravity have been proposed. A first type of positioning system involves a translating weight. U.S. Pat. No. 6,277,032 to Smith, for example, discloses a rotatable screw extending through a void in the golf club head. Rotation of the screw induces a weight to move along the length of the screw, thereby altering the position of the center of gravity. A second type of positioning system is disclosed in U.S. Pat. No. 5,916,042 to Reimers and generally involves a rotatable, eccentric weight that rotates around a central axis to alter the position of the center of gravity. A third type of positioning system, as disclosed in U.S. Pat. No. 5,385,348 to Wargo, includes a removable element of the golf club head that may be replaced by an alternate element having a different weight or moved to a different position of the golf club head, thereby altering the position of the center of gravity.